The Never War (Pendragon #3)

Bobby Pendragon has visited the alternate dimension of Denduron and waded through the endangered underwater territory of Cloral. Now Bobby once again finds himself thrust beyond the boundaries of time and space into a place that seems somewhat familiar: First Earth.
Bobby and the Traveler from Cloral—Spader—have flumed to New York City, 1937, where they must uncover the evil Saint Dane’s newest plot. But is Bobby ready for the difficult choices ahead